To transfer their male gametes to an appropriate ovary, many flowering plants produce nectar to lure insects, which inadvertently transport pollen from one flower to another. Rather than producing costly nectar, the Australian Hammer Orchids (Drakaea spp.) produce pheremones attractive to male Thynnid wasps. The large central flower petal, the labellum, attractive to insects in typical orchids, has been modified to resemble a flightless female wasp. When a male wasp attempts to carry the flower away, the hinged stem knocks the wasp into the column (a structure bearing the stamens and pistil), dusting wasp with pollen and possibly transferring pollen the wasp had picked up elsewhere to the stigma.